Objectives
This survey was designed to explore the implications of institutional change during the process of East German transformation for the lives of those born in the GDR in 1971. Because respondents in this cohort turned 18 in 1989, they had left general education before German unification, but had not yet been (fully) integrated in the East German employment system. This raises the question of whether the findings of transformation research, which had previously focused on those already integrated in the East German employment system, also apply to the 1971 cohort.

• The project thus focused first on changes in patterns of career entry during the transformation of East German society. How were educational and occupational decisions that had been made before the collapse of the Berlin Wall – i.e., under completely different social conditions and based on entirely different visions of the future – revised in the light of the new situation?
  
• Second , particular attention was paid to changes in the process of family formation. Can the post-1989 decline in the East German birth rate, to which this cohort made a major contribution, be interpreted as an adjustment to West German behavioral patterns or as a temporary shift in response to higher levels of economic uncertainty during the structural upheavals of the time?

Questionnaire Design
Based on the instrument implemented in the "Life Courses and Historical Change in the German Democratic Republic" study (LV-DDR), a standardized, computer-assisted interview procedure that could be conducted either by telephone or in face-to-face interviews (combined CATI/CAPI strategy) was developed. In a pretest, the comprehensibility and practicability of the instrument as well as its acceptance among respondents was tested. In the interviews, data on the respondents' family of origin, residential history, general education and vocational/professional training, employment history, partnership and children, as well as their membership of groups and political organizations, current attitudes to political parties, social networks, and future perspectives were collected retrospectively using empirical and quantitative interview methods (see Codebuch, pdf format, 608 KB). These data made it possible to reconstruct the life histories of the 1971 GDR birth cohort in detail.

Sample Design
A master sample drawn from the central register of the former GDR in October 1990 provided the basis for the survey (see "Sample Design" in the LV-DDR study). By using this master sample, it was possible to ensure that mobile target persons, i.e., those members of the 1971 GDR birth cohort who had moved to West Germany after reunification in October 1990, were included in the parent sample and could be chased up and surveyed at their new address. Comparison of the addresses with the Federal Office of Statistics data (1992) revealed that the master sample did not include enough addresses from places of the smallest size. The quota of addresses in places of this size was thus increased by 30 percent when the sample was drawn. Furthermore, the number of women was increased slightly to ensure a gender ratio of 50:50. The sample of respondents born in the GDR in 1971 was drawn from this slightly modified master sample.

Data Collection
The 1971 East German cohort was surveyed between May 1996 and January 1998; a total of 1,816 addresses were released to the field. The number of realized and usable cases is 610 – equivalent to a coverage rate of 49.5% (see Table 1), slightly less than that achieved in the LV-DDR study.

Table 1: Coverage and Reasons for Non-Participation

At 41.5%, the proportion of target persons who refused to participate in the study was very high. Moreover, because a relatively long period elapsed between the drawing of the sample (October 1990) and the interview (May 1996 to January 1998), and despite great efforts to ascertain target persons' current addresses, the rate of neutral non-response (address unknown, flat uninhabited, target person unknown, target person moved, target person deceased) was much higher than usual in life history studies, at 32.1%.

Representativeness
Against this background, it seemed appropriate to test whether the sample realized in the LV-Ost 71 study was in fact representative. Neutral non-response is assumed to be random, rather than systematic in nature, meaning that it does not lead to bias in the original sample. This relationship has not yet been adequately analyzed, however. Assuming that regionally mobile target persons, in particular, are much more difficult to contact, and that regional mobility is socially selective, the fact that losses were "neutral" does not exclude the possibility of sample bias, especially where the present cohort is concerned. To test for any sample bias, we compared selected marginal distributions of the sample realized in the LV-Ost 71 study with those of the microcensus surveys for the years 1991, 1993, 1995, and 1996. This comparison revealed that, apart from bias typical of life history surveys, deviations that can be attributed to difficulties in ascertaining target persons' current addresses also occurred in the LV-Ost 71 study. When examining intercorrelations between variables (and their change over time), however, these deviations are unimportant as long as the selection bias is taken into account.

Data Editing
The first round of data editing was conducted during the interview itself, by means of an automated data control mechanism integrated into the interview system. For example, information reported earlier was displayed on the computer screen, allowing the consistency of temporal data to be checked immediately. To gain a first impression of the most commonly occurring data errors, the unedited data set was intially screened for evident problems. In a second, far more time-consuming step, each interview was edited "by hand" at the Max Planck Institute for Human Development, Berlin (see Editionsbericht, pdf format, 260 KB). The checking and correction of the life history data was not limited to eliminating undefined codes or correcting filter errors, but also involved meticulous checks of data consistency and plausibility. Respondents were then re-contacted (see Nachrecherchebericht, pdf format, 171 KB) to clarify any ambiguities and contradictions that remained after the editing process. Finally, in an intensive data checking process, the filtering procedures and data domains, in particular, as well as the validity of temporal overlaps of episodes between different domains were checked once more (see Bericht über die Prüfung der Daten, pdf format, 202 KB).

Notes on Data Analysis
The public-use file for the "East German Life Courses After Unification" study (LV-Ost Panel) available from the Central Archive for Empirical Social Research (ZA) in Cologne comprises individual SPSS data files for each domain surveyed. For reasons of data protection, the public-use files were factually anonymized in the same way as for the predecessor study, the LV-DDR study. Any direct references to places and all open-ended responses were removed. The original "questionnaire number" was replaced by a new ID number produced by a random generator. The ordering of cases was also changed, such that no direct links can be made between the public-use files and the questionnaires themselves.

Documentation (Downloads, in German)